testing: Add code test coverage reporting.

Fixes #38.

tools/.coveragerc

@@ -0,0 +1,24 @@
+[report]
+# Regexes for lines to exclude from consideration
+exclude_lines =
+    # Re-enable the standard coverage pragma
+    nocoverage
+    # Don't complain if non-runnable code isn't run:
+    if False:
+    # Don't require coverage for base class NotImplementedErrors
+    raise NotImplementedError()
+    # Don't require coverage for test suite AssertionError -- they're usually for clarity
+    raise AssertionError
+    # Don't require coverage for Python 2/3 variations; it's impossible to cover on both
+    if six.PY3:
+    if six.PY2:
+    # Don't require coverage for __unicode__ statements just used for printing
+    def __unicode__[(]self[)]:
+
+[run]
+source = zulip_bots, zulip_botserver
+omit =
+    # Parts of the test runner infrastructure
+    tools/test-main
+    tools/test-bots
+    tools/test-botserver